Date of Completion

Spring 4-21-2023

Thesis Advisor(s)

Vito Moreno

Honors Major

Mechanical Engineering

Disciplines

Manufacturing | Metallurgy | Structures and Materials

Abstract

The project aimed to investigate the effects of tempering temperature on metals used for gas turbine engine fan cases as a major relevant concern is containing blades in during blade-out events. There are three ways to accomplish this: using a thicker metal, incorporating different materials into the case, or heat treating the metal. This project focused on the third solution: reviewing the impact toughness and hardness of fractured samples and their equivalent ductile-to-brittle transition shear faces. Given its availability, 1045 steel, as opposed to aerospace grade metals, was used for in-house testing. The data obtained from these experiments were then combined with findings from previous research conducted at other institutions to draw final conclusions. This study’s initial hypothesis was that increasing the tempering temperature on metals would lead to greater impact toughness and therefore better resistance against blade-out events. The data showed, however, that while 1045 steel demonstrated this correlation, aerospace-grade metals used in other studies did not. Instead, they showed that the trend only worked within certain ranges of temperatures. At specific temperatures, the impact toughness began to decrease despite the temperature increasing. The study concluded that using tempering as a method of increasing impact toughness is feasible but would require further experimentation to determine the optimal duration and temperature of tempering for fan case applications. Future investigations include finding temperature and time limits for individual metals to observe when the impact toughness stops increasing, as well as exploring other properties that are affected in the tempering process.

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